Does a glass of milk bring on cramps, diarrhea and gas? If so, how do you build strong bones to avoid osteoporosis? From tofu, almonds, leafy greens, canned salmon and more, here are 9 foods that will help you get your daily calcium when you're lactose intolerant. Plus, how much do you know about food? Take our quiz to find out…

Dairy products are a woman’s best friend for calcium. But if you’re lactose intolerant and can’t drink milk or eat ice cream and cheese, you’re at risk for osteoporosis.

When your body doesn’t get enough of this essential mineral, it pulls it from your bones, making them progressively weaker, says Michael F. Holick, Ph.D., M.D., professor of medicine at Boston University Medical Center and editor of The Vitamin D Solution (Penguin).

Women 50 and younger need at least 1,000 milligrams (mg) of calcium a day for strong bones and teeth as well as other body processes, including blood clotting, muscle contraction, digestion, nerve function and getting nutrients into cells.

Those 51 or older require a minimum of 1,200 mg daily, according to new guidelines from the Institute of Medicine, an arm of the National Academy of Science.

So if you avoid dairy products, you have to work hard to get enough calcium through other foods and supplements, says registered dietitian Susan Kasik-Miller, M.S., clinical dietitian at Sacred Heart Hospital in Eau Claire, Wis.

What can dairy-dodging women do to bone up? Read on to find out other top calcium sources.

1. TofuA typical serving size – a quarter block of tofu – has 163 mg, or a tenth of the recommended dietary amount (RDA) of calcium, according to the USDA Nutrient Database for Standard Reference.

Dish it up:Tofu is delicious in stir-fries, salads and soups. Or use it to make lactose-free meat casseroles and desserts.

Other good calcium sources include broccoli, Chinese cabbage and kale. But avoid spinach, which is loaded with oxalates, a type of salt that blocks calcium absorption, says registered dietitian Joy Blakeslee, culinary and nutrition center director at Publicis Culinary and Nutrition Center in Seattle.

6. Soy nutsThese are soybeans that have been soaked in water and baked until crisp and brown. They come in oodles of flavors – from paprika to chocolate- and yogurt-covered – are high in protein and have 261 mg of calcium per cup.

How to eat them:Take a baggie along for energy on the go.

Satisfy your sweet tooth with this snack: Mix 4 cups of soy nuts with 1/2 cup maple syrup. Spread on a cookie sheet and bake them again for 10-12 minutes at 350 degrees.

7. Canned salmonThree ounces of canned salmon contains 181 mg of calcium. Canned has more calcium than fresh because it contains small bones you can eat. Plus, it’s rich in protein and heart-healthy omega-3 fatty acids.

Dish it up: Enjoy salmon plain on crackers, or in salads, fish soups, stews and casseroles.

“Some women discover they can gradually reintroduce dairy products by eating small amounts at a time; others find they can’t tolerate any,” she says.

For example, you may be able to eat yogurt, which contains as much calcium and protein as a glass of milk – 415 mg per cup – but less lactose.

That’s because the live bacteria (lactococcus and lactobacillus) that ferment milk reduces the milk sugar, says registered dietitian Dee Sandquist, M.S., spokeswoman for the American Dietetic Association.

Also, try lactose-free dairy products, which have as much calcium and protein as regular cow’s milk and may be fortified with vitamin D, advises Blakeslee. The vitamin is needed to help your body use calcium effectively.

Dish it up: Enjoy yogurt by the cup or glass, substitute it for regular milk in cooking and baking, and use it to make smoothies.

“Fruits and vegetables only have a fourth or sixth as much calcium as dairy products,” she says. “You need to eat a lot of them to meet your calcium needs.”

But the shelves are packed with calcium supplements. How do you know which to choose?

The most common supplements are calcium carbonate and calcium citrate, says Kasik-Miller.

Calcium carbonate has the highest amount of elemental calcium – 40%. It’s not expensive – $8 online for 100 capsules – and best absorbed when taken with food.

Calcium citrate, with 21% elemental calcium, costs more, $11 online for 100 capsules. But for postmenopausal women, calcium citrate is better at preventing bone loss, produces higher serum calcium levels and is better absorbed than calcium carbonate, according to a comparison of calcium supplements published by the American Academy of Family Physicians. It’s best to take all calcium supplements with meals to further boost absorption. Many calcium supplements also contain vitamin D and magnesium, which improve absorption.

Holick advises taking a calcium supplement with vitamin D because food and exposure to sunlight don’t necessarily provide the minimum 600 IU (international units) now recommended by the IOM for women under 71. The Office of Dietary Supplements at the National Institutes of Health says healthy adults can safely take up to 4,000 IU.

“If you live in a rainy climate, are vegetarian or vegan, wear sunscreen or have dark skin, you may not be getting enough vitamin D, since only a few foods have it, including egg yolks, salmon, some mushrooms and vitamin D-fortified foods,” Holick says.

To get the most from a supplement, follow these tips:

Look for supplements labeled lead-free (or the United States Pharmacopeia (USP), symbol, which means the product meets official standards for purity, quality, strength and consistency), according to the Linus Pauling Institute at Oregon State University. Besides the danger of lead poisoning, which causes problems with the central nervous system, digestion and kidney, the heavy metal blocks absorption of calcium.

If you’re on iron supplements, take them two hours before or after you take calcium supplements to get the maximum benefit from both minerals. Calcium can interfere with iron absorption.

If you’re taking acid blockers for indigestion, reflux or other gastrointestinal conditions, take calcium citrate (which does not require an acidic environment to be absorbed) instead of calcium carbonate, according to the Osteoporosis Prevention and Treatment Clinic (OPTC) at the University of Alabama at Birmingham.

Take supplements 2-3 times daily. Your body can absorb only 500-600 mg of calcium at a time, according to the OPTC.

If your calcium tablets cause bloating, flatulence or constipation, take them with meals or try a different form, such as a gel capsule. Tablets could contain binders such as corn starch or microcrystalline cellulose.

How Much Do You Know About Food?Aside from knowing which foods you love to curl up with, how much do you really know about the history and fun facts of your favorite foods? Find out now.

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